Driving hammer



March 21, 1961 w. R. FAIRCHILD DRIVING HAMMER Filed Nov. 29, 1957 INVENTOR WILLIAM R. FAIRCHILD HeZ ATTORNEY United States Patent DRIVING HAMMER William R. Fairchild, W. R. Fairchild Construction Co., R0. 130x31, Hattieshurg, Miss.

Filed Nov. 29,1957, Ser. No. 699,788

4 Claims. (Cl. 121-13) This inventionrelates to'an improved pneumatic hammer, especially-steam hammers, for driving pile.

Steam hammers are important for driving pile into the earth in order to obtain suitable foundation or support in building bridges, roads and the like. Such hammers are generally positioned between guide bars or hammer leads which are mounted in a suitable frame positioned above the pile to be driven. When the pile is to be driven, the hammer is lowered so that the weight of the steam hammer rests on the pile. As the ram in the steam hammer is operated, the force of the blows of the ram striking the top of the pile forces the pile into the earth.

As a general rule, such steam hammers are large and heavy. An average steam hammer which has a piston stroke of 3 feet is about 12 feet in height and weighs about 11,000 pounds. In such a hammer, the ram or the striking part of the machine weighs about 5,000 pounds, and with a three foot stroke of the ram, a force of 15,000 foot pounds of striking force is imparted to the top of the pile.

With so much weight of the steam hammer and powerful striking force of the ram within the steam hammer involved, the machine is subjected to tremendous shock and vibration, and the useful life of the parts of the steam hammer is relatively short.

It is therefore an object of the present invention to provide a steam hammer in which the useful life of the parts of the hammer is increased.

Another object is to provide a steam hammer in which the parts which are subjected to severe shock and vibration are cushioned and thereby prevent frequent breakdown of the machine.

Another object is to provide a specially shaped ram point on the ram portion of the steam hammer which Will at all times present a uniform striking surface on the top of the pile being driven.

Other objects and benefits of my invention will be apparent to those skilled in the art from the following description and claims with respect to my improved steam hammer.

Figure 1 is a front view of a steam hammer partly in section positioned above a pile cap.

Figure 2 is a side elevation in section on line 2-2 of a steam hammer placed above a pile cap.

Referring to the drawing, the steam hammer comprises ram which is positioned at the end of piston rod 12. At the other end of piston rod 12, a piston 14 is mounted which moves within the cylinder 16 as steam enters the cylinder from steam chest 18. The entry of the steam 18 is controlled by rotary valve 20.

Ram 10 is slidably mounted on four columns 22, the columns passing through the body of the ram and being spaced 90 from each other, that is, the four columns are positioned adjacent to the corners of the ram 10. The columns 22 extend from and through the base 24 of the steam hammer through the body of ram 10, through the base 26 of cylinder 16 and through bosses 27 at top of cylinder 16 and adjacent to cylinder cap 28.

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Coil springs 30 are mounted on each of the four columns at the steam hammer base 24, the cylinder base 26 and the cylinder cap 28. Each spring is resiliently locked in position by nuts 32 which are screwed on the threaded portions of columns 22 at the points 24, 26and 28 previously mentioned. If desired, the coil springmounted on bosses 27 on top of the cylinder cap 28 may be removed and the columns 22 discontinued after passing through cylinder base 26. However, in order to obtain the most efficient absorption of shock and vibration, it is preferable that the third spring be mounted on the cylinder bosses 27 as shown in the drawing.

Similarly, a coiled spring 34' is mounted at the base of piston rod 12 within the body of ram 10. Spring 34 is held resiliently in place by aplate 36. A spring 38 is also mounted at the'base of slide bar 40.

The ram point 42 projects below the base or main body portion of ram 10 and the lower edge 44 of the ram point is outwardly curved or convex in shape. The convex portion 44 of the ram point 42 permits use of uneven ended piling and it shapes out the top of the uneven ended piling so that efiicient driving may be accomplished.

It is necessary to have at least two coiled springs mounted on each of the four columns 22 as described, but it is preferable that three springs be mounted on each column in order to suitably absorb the shock and thereby extend the life of the steam hammer thereby substantially reducing the need of service and repairs. These springs on each column are tightened down and held at almost full compression by nuts 32, thus allowing a small amount of slack for cushioning eifect but at the same time locking and holding the columns 22 securely in place.

In use, the cap 46 is mounted on top of the pile to be driven. The steam hammer is then lowered by cable passed through sheave 48 until cap 46 is positioned in the hollowed out portion 48 of the hammer base 24. As the ram 10 is moved up and down by the steam piston 14, the convex shaped point 44 on ram point 42 strikes the top surface of the wooden cushion block in the pile cap 46 which rests on the pile being driven. Since the surface of the point is convex in shape, the top of the cushion block will be hollowed out to some degree as the ram point strikes the top of the cushion block in the pile cap, thereby the pile cap adjusts itself to the uneven end of the pile.

As pointed out above, the steam hammer is a heavy piece of mechanism, and since the ram point strikes a solid pile, the impact force is tremendous when the ram 10 falls through the distance of the piston stroke which usually is three feet. The spring 30, 34 and 38 absorb the greater portion of the shock and vibration, and through such resilient mounting the shock on the apparatus is absorbed.

Various changes may be made in this embodiment of my invention as will be apparent to those skilled in the art within the scope of the appended claims.

I claim:

1. A steam hammer comprising a cylinder, at reciprocating piston within said cylinder, a piston rod having one end fixed to the piston extending through the cylinder base and resiliently anchored to a movable ram, four columns each of which extends from and through the base of the steam hammer through the body of the ram and through the cylinder base, and resilient means mounted on each column at the base of the steam hammer and the base of the cylinder.

2. A steam hammer as defined in claim 1, and wherein each of the four columns extends from and through the base of the steam hammer, through the .body of the ram and through the cylinder base and the bosses at the top of the cylinder, and resilient means mounted on each column at the base of the steam hammer and at the cylinder base and the bosses at top of the cylinder.

3. A-steam' hammer comprising a cylinder; a reciprocating piston within said cylinder, a piston rod having one end fixed to the piston extending through the cylinder base and resiliently anchored to a movable ram, four columns each of which extends from the base of the steam hammer through the body of the ram and through the cylinder base, and coiled springs mounted on each column at the base of the steam hammer and the base of the cylinder, said coiled springs held resiliently in place through contact at each end of the springs with parts of the steam hammer.

4. A steam hammer comprising a cylinder, a reciprocating piston within said cylinder, a piston rod having one end fixed to the piston extending through the cylinder base and resiliently anchored to a movable ram, four columns each of which extends from the base of the steam hammer through the body of the ram and through the cylinder base and through the bosses at top of the cylinder, and coiled springs mounted on each column at the base of the steam hammer and the base of the cylinder and on the bosses at top of the cylinder, said coiled springs held resiliently in place through contact at each end of the springs with parts of the steam hammer.

References Cited in the file of this patent UNITED STATES PATENTS 1,168,850 Campbell Jan. 18, 1916 1,415,905 Stevens May 16, 1922 1,480,304 Saliger Jan. 8, 1924 2,447,886 Worth Aug. 24, 1948 2,512,763 Bergmann June 27, 1950 2,558,165 Anderson June 26, 1951 2,598,455 Smith May 27, 1952 2,798,363 Hazak et a1. July 9, 1957 

